Computer Operating System Questions and Answers

Answer: C

The command is UNDELETE.

MS-DOS 5.0 and later include UNDELETE, which recovers a deleted file as long as its disk space has not yet been reused. That is why it should be used immediately after the deletion.

DO NOT DELETE, NO DELETE and ONDELETE are not MS-DOS commands.

UNDELETE works because deleting a file in DOS only marks its directory entry and frees its clusters; the data stays on the disk until new files overwrite it, which is why the recovery should be attempted at once.

Answer: B

The one that is not an operating system is COBOL.

COBOL (Common Business-Oriented Language) is a programming language, developed around 1959 for business data processing and still used in banking and government systems.

Windows XP, Windows 10 and Unix are all operating systems, the software that manages a computer's hardware and runs other programs.

Answer: D

The value is 777.

In octal chmod notation each digit gives the permissions of one class (owner, group, others), and each digit is the sum of read = 4, write = 2 and execute = 1. Full read, write and execute is 4 + 2 + 1 = 7, so 7 for every class is 777. (The paper's 'owner, user, others' means owner, group, others.)

111 gives execute only, 333 gives write and execute, and 555 gives read and execute to everyone; none of them grants all three permissions.

Answer: B

You find it under CPU.

In Windows 11, open Task Manager (Ctrl + Shift + Esc) and go to the Performance tab. Selecting CPU shows the processor's name, speed and utilisation, together with the number of Cores and Logical processors.

The Memory, Ethernet and Disk panes on the same tab show RAM, network and storage figures, not the processor's cores.

Answer: A

Defragmenting in Windows 11 means to Optimize Disk.

The built-in tool is called Defragment and Optimize Drives. On a hard disk it gathers the scattered pieces of files into contiguous blocks so they can be read faster; on a solid-state drive it sends TRIM commands instead. Either way, it works on the disk drives.

RAM and the CPU are not defragmented by this tool, so those options and 'None of these' are wrong.

Answer: C

Correct answer: Real time system

A real-time system must respond within a deadline set by the process it controls, because a correct answer that arrives late is useless - the world has moved on. Batch and time-sharing systems aim at throughput and fair response instead, with no guaranteed deadline.

Answer: B

Correct answer: Public domain program

A public domain program carries no copyright restriction, so anyone may compile, use, change and redistribute it freely. Shareware is copyrighted and may be tried before purchase but must then be paid for, and firmware describes where a program is stored rather than its licence.

Answer: C

Correct answer: a program in execution

A program is a passive file of instructions on disk; a process is that program actually running, with a program counter, registers, a stack, its own address space and an entry in the process table. One program may have several processes running from it at once.

Answer: C

Correct answer: Windows 8

Windows 8 dropped the Start button from the desktop taskbar, replacing the Start menu with the full-screen Start screen - a change so unpopular that Windows 8.1 restored the button and Windows 10 restored the menu. Vista and 7 both have it.

Answer: D

Correct answer: multitasking

Running more than one program at a time requires multitasking: the system must hold several programs, keep the state of each, and switch the processor between them quickly enough that all appear to advance together. Virtual memory helps by letting them all be resident, but it is the switching that makes concurrency.